Box by the border

On Saturday (January 7) I was on a road at the very southwest corner of the US — south of San Diego, just north of the border wall and a few miles from the Pacific. (Click on the "Location" below for a map.) It's a bizarre place, partly because the US side of the border is rural and the Mexican side has a freeway and Tijuana just behind it. This mailbox stood out:

It's a bit hard to tell, but the black band underneath the mailbox is a tire.